Resin composition, prepreg, resin sheet, metal foil-clad laminate, and printed circuit board

ABSTRACT

It is intended to provide a resin composition that serves as a raw material for a printed circuit board excellent in heat resistance after moisture absorption and is excellent in moldability. The resin composition of the present invention contains a maleimide compound, a silane compound having a carbon-carbon unsaturated bond and a hydrolyzable group or a hydroxy group, a silane compound having an epoxy skeleton and a hydrolyzable group or a hydroxy group, and an inorganic filler.

TECHNICAL FIELD

The present invention relates to a resin composition, a prepreg, a resinsheet, a metal foil-clad laminate, and a printed circuit board.

BACKGROUND ART

The high integration or high-density packaging of each component forsemiconductor packages has been increasingly accelerated in recent yearsas semiconductor packages widely used in electronics, communicationdevices, personal computers, etc. have been more highly functionalizedor miniaturized. Along with this, the difference in the coefficient ofthermal expansion between a semiconductor device and a printed circuitboard for semiconductor plastic packages causes the undesired warpage ofsemiconductor plastic packages. Various approaches against this problemhave been attempted.

One example of the approaches includes reduction in thermal expansion ofinsulating layers for use in printed circuit boards. This approach is tosuppress the warpage by bringing the coefficient of thermal expansion ofa printed circuit board closer to the coefficient of thermal expansionof a semiconductor device and is currently being actively addressed (seee.g., Patent Documents 1 to 3).

In addition to the reduction in thermal expansion of printed circuitboards, increase in the rigidity of laminates (high rigidity) orincrease in the glass transition temperatures of laminates (high Tg) hasbeen studied as an approach for suppressing the warpage of semiconductorplastic packages (see e.g., Patent Documents 4 and 5).

CITATION LIST Patent Document

-   Patent Document 1: Japanese Patent Application Laid-Open No.    2013-216884-   Patent Document 2: Japanese Patent No. 3173332-   Patent Document 3: Japanese Patent Application Laid-Open No.    2009-035728-   Patent Document 4: Japanese Patent Application Laid-Open No.    2013-001807-   Patent Document 5: Japanese Patent Application Laid-Open No.    2011-178992

SUMMARY OF INVENTION Technical Problem

The approach based on the high Tg of laminates mentioned above improvesan elastic modulus during reflow and is therefore effective forreduction in the warpage of semiconductor plastic packages. However, theapproach based on the high Tg causes deterioration in heat resistanceafter moisture absorption caused by elevated crosslink density, or voidformation caused by deteriorated moldability. This often becomes apractical problem in the field of electronic materials, which arerequired to have very high reliability. Thus, an approach of solvingthese problems is demanded.

The present invention has been made in light of these circumstances, andan object of the present invention is to provide a metal foil-cladlaminate and a printed circuit board excellent in heat resistance aftermoisture absorption, and a resin composition, a prepreg, and a resinsheet that serve as raw materials therefor and are excellent inmoldability.

Solution to Problem

The present inventors have conducted diligent studies to achieve theobjects and consequently found that a resin composition that serves as araw material for a printed circuit board contains a plurality ofparticular components, whereby excellent heat resistance after moistureabsorption and moldability is obtained. On the basis of the finding, thepresent invention has been completed.

Specifically, the present invention is as described below.

[1]

A resin composition containing a maleimide compound, a silane compoundhaving a carbon-carbon unsaturated bond and a hydrolyzable group or ahydroxy group, a silane compound having an epoxy skeleton and ahydrolyzable group or a hydroxy group, and an inorganic filler.

[2]

The resin composition according to [1], wherein the resin compositioncontains, as the silane compound having a carbon-carbon unsaturated bondand a hydrolyzable group or a hydroxy group, a silane compound having astyrene skeleton and a hydrolyzable group or a hydroxy group, and/or asilane compound having a (meth)acryl skeleton and a hydrolyzable groupor a hydroxy group.

[3]

The resin composition according to [2], wherein the resin compositioncontains, as the silane compound having a carbon-carbon unsaturated bondand a hydrolyzable group or a hydroxy group, a silane compound having astyrene skeleton and a hydrolyzable group or a hydroxy group.

[4]

The resin composition according to [2] or [3], wherein the resincomposition contains, as the silane compound having a styrene skeletonand a hydrolyzable group or a hydroxy group, a compound represented bythe following formula (A):

wherein R₈ represents the hydrolyzable group or the hydroxy group; R₉represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms;when a plurality of R₈ or R₉ are present, the plurality of R₈ or R₉ arethe same as or different from each other; and k represents an integer of1 to 3.[5]

The resin composition according to [2], wherein the resin compositioncontains, as the silane compound having a (meth)acryl skeleton and ahydrolyzable group or a hydroxy group, a compound represented by thefollowing formula (C):

wherein R₁₃ represents the hydrolyzable group or the hydroxy group; R₁₄represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms;when a plurality of R₁₃ or R₁₄ are present, the plurality of R₁₃ or R₁₄are the same as or different from each other; R₁₅ represents a hydrogenatom or a methyl group; R₁₆ represents an alkylene group having 2 to 10carbon atoms; and j represents an integer of 1 to 3.[6]

The resin composition according to any one of [1] to [5], wherein theresin composition contains, as the silane compound having an epoxyskeleton and a hydrolyzable group or a hydroxy group, a compoundrepresented by the following formula (D):

wherein R₁₀ represents the hydrolyzable group or the hydroxy group; R₁₁represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms;when a plurality of R₁₀ or R₁₁ are present, the plurality of R₁₀ or R₁₁are the same as or different from each other; R₁₂ represents an alkylenegroup having 1 to 10 carbon atoms; and m represents an integer of 1 to3. [7]

The resin composition according to any one of [1] to [6], furthercontaining an alkenyl-substituted nadimide.

[8]

The resin composition according to [7], wherein the resin compositioncontains, as the alkenyl-substituted nadimide, a compound represented bythe following formula (1)

wherein each R₁ independently represents a hydrogen atom or an alkylgroup having 1 to 6 carbon atoms, and R₂ represents an alkylene grouphaving 1 to 6 carbon atoms, a phenylene group, a biphenylene group, anaphthylene group, or a group represented by the following formula (2)or (3):

wherein R₃ represents a methylene group, an isopropylidene group, or asubstituent represented by CO, O, S, or SO₂, and

wherein each R₄ independently represents an alkylene group having 1 to 4carbon atoms, or a cycloalkylene group having 5 to 8 carbon atoms.[9]

The resin composition according to [7] or [8], wherein the resincomposition contains, as the alkenyl-substituted nadimide, a compoundrepresented by the following formula (4) and/or (5):

[10]

The resin composition according to any one of [1] to [9], wherein theresin composition contains, as the maleimide compound, at least onecompound selected from the group consisting ofbis(4-maleimidophenyl)methane,2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane,bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, polytetramethyleneoxide-bis(4-maleimidobenzoate), and a maleimide compound represented bythe following formula (6):

wherein each R₅ independently represents a hydrogen atom or a methylgroup, and n₁ represents an integer of 1 or larger.[11]

The resin composition according to any one of [1] to [10], furthercontaining a cyanate ester compound.

[12]

The resin composition according to [11], wherein the resin compositioncontains, as the cyanate ester compound, a compound represented by thefollowing formula (7) and/or (8):

wherein each R₆ independently represents a hydrogen atom or a methylgroup, and n₂ represents an integer of 1 or larger, and

wherein each R₇ independently represents a hydrogen atom or a methylgroup, and n₃ represents an integer of 1 or larger.[13]

The resin composition according to any one of [1] to [12], wherein theinorganic filler contains at least one selected from the groupconsisting of silica, alumina, and aluminum nitride.

[14]

The resin composition according to any one of [1] to [13], wherein thecontent of the inorganic filler in the resin composition is 100 to 1100parts by mass based on 100 parts by mass in total of component(s)constituting a resin in the resin composition.

[15]

The resin composition according to any one of [1] to [14], wherein theinorganic filler is surface-treated in advance with the silane compoundhaving a carbon-carbon unsaturated bond and a hydrolyzable group or ahydroxy group, and the silane compound having an epoxy skeleton and ahydrolyzable group or a hydroxy group.

[16]

A prepreg including a base material and a resin composition according toany one of [1] to [15], the base material being impregnated or coatedwith the resin composition.

[17]

The prepreg according to [16], wherein the base material is at least onematerial selected from the group consisting of E glass cloth, T glasscloth, S glass cloth, Q glass cloth, and an organic fiber cloth.

[18]

A resin sheet including a support and a resin composition according toany one of [1] to [15], the support being coated with the resincomposition.

[19]

A laminate having one or more layers of at least one material selectedfrom the group consisting of a prepreg according to [16] and [17] and aresin sheet according to [18], the laminate including a cured product ofa resin composition contained in at least one material selected from thegroup consisting of the prepreg and the resin sheet.

[20]

A metal foil-clad laminate having at least one material selected fromthe group consisting of a prepreg according to [16] and [17] and a resinsheet according to [18], and a metal foil disposed on one side or bothsides of at least one material selected from the group consisting of theprepreg and the resin sheet, the metal foil-clad laminate including acured product of a resin composition contained in at least one materialselected from the group consisting of the prepreg and the resin sheet.

[21]

A printed circuit board including an insulating layer and a conductorlayer formed on a surface of the insulating layer, wherein theinsulating layer contains a resin composition according to any one of[1] to [15].

Advantageous Effects of Invention

The present invention can provide a metal foil-clad laminate and aprinted circuit board excellent in heat resistance after moistureabsorption, and a resin composition, a prepreg, and a resin sheetexcellent in moldability.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment for carrying out the present invention(hereinafter, also referred to as the “present embodiment”) will bedescribed in detail. However, the present invention is not intended tobe limited by the present embodiment described below. Various changes ormodifications may be made in the present invention without departingfrom the spirit of the present invention.

The resin composition of the present embodiment contains a maleimidecompound, a silane compound having a carbon-carbon unsaturated bond anda hydrolyzable group or a hydroxy group (hereinafter, also referred toas an “unsaturated bond-containing silane compound”), a silane compoundhaving an epoxy skeleton and a hydrolyzable group or a hydroxy group(hereinafter, also referred to as an “epoxysilane compound”), and aninorganic filler. In this resin composition, which contains themaleimide compound and the unsaturated bond-containing silane compound,the unsaturated bond-containing silane compound bonded at itshydrolyzable group or hydroxy group to the inorganic filler is alsobonded at its unsaturated bond to the maleimide compound to therebyenhance the adhesion between the inorganic filler and the maleimidecompound. By combined use of the epoxysilane compound, which is capableof being bonded to the inorganic filler but has low reactivity with themaleimide compound, with these components, the epoxysilane compound actsas a dispersant for the inorganic filler to thereby enhance thedispersibility of the inorganic filler in an insulating layer, leadingto excellent moldability. In addition to the strong bonding between theinorganic filler and the maleimide compound via the unsaturatedbond-containing silane compound, the improvement in the dispersibilityof the inorganic filler by the epoxysilane compound presumably reducesthe occurrence of defects such as voids and suppresses the deteriorationof heat resistance after moisture absorption. However, possible factorsare not limited to those described above.

The resin composition of the present embodiment exhibits excellentmoldability and serves as a raw material for a metal foil-clad laminateand a printed circuit board that exhibit excellent heat resistance aftermoisture absorption. As a result, the metal foil-clad laminate and theprinted circuit board are also excellent in insulation reliability.

The maleimide compound used in the present embodiment is notparticularly limited as long as the compound has one or more maleimidegroups in the molecule. Specific examples thereof includeN-phenylmaleimide, N-hydroxyphenylmaleimide,bis(4-maleimidophenyl)methane,2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane,bis(3,5-dimethyl-4-maleimidophenyl)methane,bis(3-ethyl-5-methyl-4-maleimidophenyl)methane,bis(3,5-diethyl-4-maleimidophenyl)methane, a maleimide compoundrepresented by the formula (6) set forth below, prepolymers of thesemaleimide compounds, and prepolymers of the maleimide compounds andamine compounds. These compounds can be used singly or in a form of asuitable mixture of two or more thereof.

Among them, bis(4-maleimidophenyl)methane,2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane,bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, polytetramethyleneoxide-bis(4-maleimidobenzoate), or a maleimide compound represented bythe following formula (6) is preferred, and a maleimide compoundrepresented by the following formula (6) is particularly preferred. Whenthe resin composition contains such a maleimide compound, the resultingcured product tends to have better heat resistance and glass transitiontemperature.

In the formula (6), each R₅ independently represents a hydrogen atom ora methyl group and is particularly preferably a hydrogen atom. In theformula, n₁ represents an integer of 1 or larger. The upper limit of n₁is preferably 10, more preferably 7.

In the resin composition of the present embodiment, the content of themaleimide compound is preferably determined according to the ratio ofthe number of functional group between the number of alkenyl groups (a)as a functional group in an optionally contained alkenyl-substitutednadimide and the number of maleimide groups (β) in the maleimidecompound ([β/α]) as mentioned later. The content of the maleimidecompound is preferably 15 to 70 parts by mass, more preferably 20 to 45parts by mass, based on 100 parts by mass in total of component(s)constituting a resin (also including components that form resins bypolymerization; the same holds true for the description below) in theresin composition. When the content of the maleimide compound fallswithin such a range, the resulting resin composition can be excellent inmoldability even with an inorganic filler, and has curability andelastic modulus under heat such as flexural modulus at, for example,250° C. during curing or flexural modulus at a solder reflowtemperature, and a printed circuit board or the like excellent indesmear resistance and chemical resistance can be obtained.

The resin composition of the present embodiment contains an unsaturatedbond-containing silane compound in order to enhance the adhesion betweenthe maleimide compound and the inorganic filler. The unsaturatedbond-containing silane compound is not particularly limited as long asthe unsaturated bond-containing silane compound is a silane compoundhaving a carbon-carbon unsaturated bond and a hydrolyzable group or ahydroxy group. In this context, the “carbon-carbon unsaturated bond”used herein means an ethylenic unsaturated bond or an acetylenicunsaturated bond. Examples of the hydrolyzable group include: alkoxygroups such as a methoxy group, an ethoxy group, and a propoxy group;and halogen atoms such as a chlorine atom and an iodine atom (the sameholds true for the description below).

Examples of the unsaturated bond-containing silane compound include asilane compound having a styrene skeleton and a hydrolyzable group or ahydroxy group (hereinafter, referred to as a “styryl silane compound”),a silane compound having a (meth)acryl skeleton (acryl skeleton ormethacryl skeleton) and a hydrolyzable group or a hydroxy group(hereinafter, referred to as an “acrylic silane compound”), and a silanecompound having an olefin skeleton (e.g., an octenyl group, a vinylgroup, and an allyl group) and a hydrolyzable group or a hydroxy group(hereinafter, referred to as an “olefin silane compound”). Among them,one or more silane compounds selected from the group consisting of astyryl silane compound and an acrylic silane compound are preferred inview of more effectively and reliably exhibiting the function effects ofthe present invention. Alternatively, the unsaturated bond-containingsilane compound may be any compound for use as a silane coupling agenthaving a carbon-carbon unsaturated bond and a hydrolyzable group or ahydroxy group. These unsaturated bond-containing silane compound areused singly or in combinations of two or more thereof.

The styryl silane compound is not particularly limited as long as thestyryl silane compound is a silane compound having a styrene skeletonand a hydrolyzable group or a hydroxy group. The styryl silane compoundmay be any compound for use as a silane coupling agent having a styreneskeleton and a hydrolyzable group or a hydroxy group (so-called styrylsilane coupling agent). The styryl silane compound preferably includes acompound represented by the following formula (A), in view of moreeffectively and reliably exhibiting the function effects of the presentinvention.

In the formula (A), R₈ represents the hydrolyzable group or the hydroxygroup; R₈ represents a hydrogen atom or an alkyl group having 1 to 3carbon atoms; when a plurality of R₈ or R₉ are present, the plurality ofR₈ or R₉ are the same as or different from each other; and k representsan integer of 1 to 3.

Specific examples of the styryl silane compound includep-styryltrimethoxysilane, p-styryltriethoxysilane,p-styrylmethyldimethoxysilane, p-styrylmethyldiethoxysilane, andN-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilanehydrochloride. Among them, p-styryltrimethoxysilane orp-styryltriethoxysilane is preferred, and p-styryltrimethoxysilane ismore preferred. Examples of commercially available products includeKBM-575 and KBM-1403 (both are the names of products manufactured byShin-Etsu Chemical Co., Ltd.). These styryl silane compounds are usedsingly or in combinations of two or more thereof.

The acrylic silane compound is not particularly limited as long as theacrylic silane compound is a silane compound having a (meth)acrylicskeleton and a hydrolyzable group or a hydroxy group. The acrylic silanecompound may be any compound for use as a silane coupling agent having a(meth)acrylic skeleton and a hydrolyzable group or a hydroxy group(so-called acrylic silane coupling agent). The acrylic silane compoundpreferably includes a compound represented by the following formula (C),in view of more effectively and reliably exhibiting the functioneffects, of the present invention.

In the formula (C), R₁₃ represents the hydrolyzable group or the hydroxygroup; R₁₄ represents a hydrogen atom or an alkyl group having 1 to 3carbon atoms; when a plurality of R₁₃ or R₁₄ are present, the pluralityof R₁₃ or R₁₄ are the same as or different from each other; R₁₅represents a hydrogen atom or a methyl group; R₁₆ represents an alkylenegroup having 2 to 10 carbon atoms; and j represents an integer of 1 to3. Particularly, R₁₆ is preferably an alkylene group having 2 to 10carbon atoms, more preferably an alkylene group having 3 to 8 carbonatoms, further preferably an alkylene group having 3 to 6 carbon atoms,in view of moldability.

Specific examples of the acrylic silane compound include3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane,and methacryloxyoctyltrimethoxysilane. Among them,3-acryloxypropyltrimethoxysilane is preferred. Examples of commerciallyavailable products include KBM-5103, KBM-503, and KBM-5803 (all are thenames of products manufactured by Shin-Etsu Chemical Co., Ltd.). Theseacrylic silane compounds are used singly or in combinations of two ormore thereof.

In the resin composition of the present embodiment, the content of theunsaturated bond-containing silane compound is not particularly limitedand is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 5parts by mass, based on 100 parts by mass in total of component(s)constituting a resin in the resin composition. The content of theunsaturated bond-containing silane compound within the range describedabove leads to further improvement in heat resistance after moistureabsorption and moldability.

The resin composition of the present embodiment contains an epoxysilanecompound in order to enhance the dispersibility of the inorganic fillerand secure excellent moldability. The epoxysilane compound is notparticularly limited as long as the epoxysilane compound is a silanecompound having an epoxy skeleton and a hydrolyzable group or a hydroxygroup. The epoxysilane compound may be any compound for use as a silanecoupling agent having an epoxy skeleton and a hydrolyzable group or ahydroxy group (so-called epoxysilane coupling agent). The epoxysilanecompound preferably includes a compound represented by the followingformula (D), in view of more effectively and reliably exhibiting thefunction effects of the present invention.

In the formula (D), R₁₀ represents the hydrolyzable group or the hydroxygroup; R₁₁ represents a hydrogen atom or an alkyl group having 1 to 3carbon atoms; when a plurality of R₁₀ or R₁₁ are present, the pluralityof R₁₀ or R₁₁ are the same as or different from each other; R₁₂represents an alkylene group having 1 to 10 carbon atoms; and mrepresents an integer of 1 to 3. R₁₂ is preferably an alkylene grouphaving 2 to 10 carbon atoms, more preferably an alkylene group having 3to 8 carbon atoms.

Specific examples of the epoxysilane compound include3-glycidoxypropyltrimethoxysilane,3-glycidoxypropylmethyldimethoxysilane,3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane,glycidoxyoctyltrimethoxysilane, and2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Among them,3-glycidoxypropyltrimethoxysilane is preferred. Examples of commerciallyavailable products include KBM-403, KBM-402, KBE-403, KBE-402, KBM-4803,and KBM-303 (all are the names of products manufactured by Shin-EtsuChemical Co., Ltd.). These epoxysilane compounds are used singly or incombinations of two or more thereof.

In the resin composition of the present embodiment, the content of theepoxysilane compound is not particularly limited and is preferably 0.1to 15 parts by mass, more preferably 0.5 to 5 parts by mass, based on100 parts by mass in total of component(s) constituting a resin in theresin composition. The content of the epoxysilane compound within therange described above leads to further improvement in the dispersibilityof the inorganic filler, while it also can prevent the glass transitiontemperature (Tg) from being decreased due to the inhibition of resincuring by redundant silane compounds.

The resin composition of the present embodiment contains an inorganicfiller. The inorganic filler contributes to reduction in the thermalexpansion of a printed circuit board and improvement in elastic modulusand the coefficient of thermal conductivity. The inorganic filler is notparticularly limited as long as the inorganic filler has insulatingproperties. Examples thereof include silicas (e.g., natural silica,fused silica, amorphous silica, and hollow silica), alumina, aluminumnitride, boron nitride, boehmite, molybdenum oxide, titanium oxide,silicone rubber, hybrid silicone powder, zinc borate, zinc stannate,clay, kaolin, talc, fired clay, fired kaolin, fired talc, mica, shortglass fiber (fine glass powders such as E glass and D glass), hollowglass, and spherical glass. These inorganic fillers are used singly orin combinations of two or more thereof. Among them, silica is preferredin view of achieving lower thermal expansion, and alumina or aluminumnitride is preferred in view of achieving higher thermal conductivity.The inorganic filler may be surface-treated in advance with theunsaturated bond-containing silane compound and/or the epoxysilanecompound. A method for the surface treatment is not particularlylimited. Examples thereof include direct treatment methods such as a drytreatment method and a treatment method using slurry (wet method). A wetmethod is preferred in view of uniform treatment. Alternatively, theinorganic filler may be a commercially available surface-treatedinorganic filler.

In the resin composition of the present embodiment, the content of theinorganic filler is not particularly limited and is preferably 100 to1100 parts by mass, more preferably 100 to 700 parts by mass, based on100 parts by mass in total of component(s) constituting a resin in theresin composition. When the content of the inorganic filler falls withinthe range described above, characteristics unique to the inorganicfiller, such as low thermal expansion, high elasticity, and thecoefficient of thermal conductivity are more favorably exhibited, whilereduction in moldability can be further suppressed.

The average particle size (D50) of the inorganic filler is notparticularly limited and is preferably 0.2 to 10 μm, more preferably 2to 5 μm, because finer wiring can be formed thereby. The particle shapeof the inorganic filler is not particularly limited and is preferably aspherical or substantially spherical shape in view of moldability. Inthis context, D50 is a median size and is a size that splits themeasured particle size distribution of a powder such that the mass ofhalf of the particles being larger is equal to the mass of half of theparticles being smaller. D50 is generally measured by a wet laserdiffraction/scattering method.

The resin composition of the present embodiment preferably contains analkenyl-substituted nadimide in view of more effectively and reliablyexhibiting the function effects of the present invention. Thealkenyl-substituted nadimide is not particularly limited as long as thecompound has one or more alkenyl-substituted nadimide groups in themolecule. Specific examples thereof include a compound represented bythe following formula (1):

In the formula (1), each R₁ independently represents a hydrogen atom oran alkyl group having 1 to 6 carbon atoms, and R₂ represents an alkylenegroup having 1 to 6 carbon atoms, a phenylene group, a biphenylenegroup, a naphthylene group, or a group represented by the followingformula (2) or (3):

In the formula (2), R₃ represents a methylene group, an isopropylidenegroup, or a substituent represented by CO, O, S, or SO₂.

In the formula (3), each R₄ is independently selected and represents analkylene group having 1 to 4 carbon atoms, or a cycloalkylene grouphaving 5 to 8 carbon atoms.

A commercially available product can also be used as thealkenyl-substituted nadimide represented by the formula (1). Examples ofthe commercially available product include, but are not particularlylimited to, a compound represented by the formula (4) set forth below(BANI-M (manufactured by Maruzen Petrochemical Co., Ltd.)), and acompound represented by the formula (5) set forth below (BANI-X(manufactured by Maruzen Petrochemical Co., Ltd.)). These compounds maybe used singly or in combinations of two or more thereof.

In the resin composition of the present embodiment, the content of thealkenyl-substituted nadimide may be determined according to the ratio ofthe number of functional group between an alkenyl group, one of itsfunctional groups, and a maleimide group in the maleimide compound asmentioned later. The content of the alkenyl-substituted nadimide ispreferably 20 to 50 parts by mass, more preferably 25 to 45 parts bymass, based on 100 parts by mass in total of component(s) constituting aresin in the resin composition. When the content of thealkenyl-substituted nadimide falls within such a range, the resultingresin composition or the like can be excellent in moldability even withan inorganic filler, and be excellent in curability and elastic modulusunder heat during curing, and a printed circuit board or the likeexcellent in desmear resistance and chemical resistance can be obtained.

In the resin composition of the present embodiment, the contents of thealkenyl-substituted nadimide and the maleimide compound are specified bythe ratio between the numbers of their respective designated functionalgroups. In this context, the designated functional group of thealkenyl-substituted nadimide is alkenyl groups bonded to molecular ends,and the designated functional group of the maleimide compound ismaleimide groups.

The resin composition of the present embodiment preferably contains thealkenyl-substituted nadimide and the maleimide compound so as to satisfya relationship represented by the following formula (E), more preferablya relationship represented by the following formula (E1):

0.9≤β/α≤4.3  (E)

1.5≤β/α≤4.0  (E1)

In these formulas, α represents the total number of alkenyl groupscontained in the alkenyl-substituted nadimide in the resin composition,and β represents the total number of maleimide groups contained in themaleimide compound in the resin composition. When the functional groupratio (β/α) falls within such a range, the resulting resin compositionor the like can have a better elastic modulus under heat and easiercurability during curing, and a printed circuit board or the like can beobtained which is excellent in low thermal expansion, heat resistance,heat resistance after moisture absorption, desmear resistance, andchemical resistance.

The resin composition of the present embodiment preferably furthercontains a cyanate ester compound in addition to each componentmentioned above. By use of the cyanate ester compound, a resincomposition or the like having better moldability can be obtained, and aprinted circuit board or the like having better copper foil peelstrength can be obtained. The cyanate ester compound is used singly orin combinations of two or more thereof.

Examples of the type of the cyanate ester compound used in the presentembodiment include, but are not particularly limited to, a naphtholaralkyl-based cyanate ester represented by the formula (7) set forthbelow, a novolac-based cyanate ester represented by the formula (8) setforth below, biphenyl aralkyl-based cyanate esters,bis(3,3-dimethyl-4-cyanatophenyl)methane, bis(4-cyanatophenyl)methane,1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene,1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene,1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene,2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene,1,3,6-tricyanatonaphthalene, 4,4′-dicyanatobiphenyl,bis(4-cyanatophenyl) ether, bis(4-cyanatophenyl) thioether,bis(4-cyanatophenyl)sulfone, and 2,2-bis(4-cyanatophenyl) propane.

Among them, a naphthol aralkyl-based cyanate ester represented by thefollowing formula (7), a novolac-based cyanate ester represented by thefollowing formula (8), and a biphenyl aralkyl-based cyanate ester areparticularly preferred because of excellent flame retardancy, highcurability, and the low coefficient of thermal expansion of a curedproduct.

In this formula, each R₆ independently represents a hydrogen atom or amethyl group and is particularly preferably a hydrogen atom. In theformula, n₂ represents an integer of 1 or larger. The upper limit of n₂is preferably 10, more preferably 6.

In this formula, each R₇ independently represents a hydrogen atom or amethyl group and is particularly preferably a hydrogen atom. In theformula, n₃ represents an integer of 1 or larger. The upper limit of n₃is preferably 10, more preferably 7.

Methods for producing these cyanate ester compounds are not particularlylimited, and the cyanate ester compound used in the present embodimentmay be produced by any method existing as a cyanate ester synthesismethod. As a specific example, the cyanate ester compound can beobtained by reacting a naphthol aralkyl-based phenol resin representedby the formula (9) set forth below with cyanogen halide in the presenceof a basic compound in an inert organic solvent. An alternate methodthat may be adopted involves forming a salt of a similar naphtholaralkyl-based phenol resin and a basic compound in a solution containingwater, followed by two-phase interfacial reaction with cyanogen halidefor synthesis.

In this formula, each R₈ independently represents a hydrogen atom or amethyl group and is particularly preferably a hydrogen atom. In theformula, n₄ represents an integer of 1 or larger. The upper limit of n₄is preferably 10, more preferably 6.

The naphthol aralkyl-based cyanate ester can be selected from thoseobtained by condensing cyanic acid with a naphthol aralkyl resinobtained through the reaction of a naphthol such as α-naphthol orβ-naphthol with p-xylylene glycol, α,α′-dimethoxy-p-xylene,1,4-di(2-hydroxy-2-propyl)benzene, or the like.

In the resin composition of the present embodiment, the content of thecyanate ester compound is not particularly limited and is preferably0.01 to 40 parts by mass, more preferably 0.01 to 25 parts by mass,based on 100 parts by mass in total of component(s) constituting a resinin the resin composition. When the content of the cyanate ester compoundfalls within such a range, a resin composition or the like having bettermoldability even with an inorganic filler and having an excellentelastic modulus under heat during curing can be obtained, and a printedcircuit board or the like also having better desmear resistance andchemical resistance can be obtained.

The resin composition of the present embodiment may be supplemented witha resin other than those mentioned above (hereinafter, referred to as an“additional resin”) without impairing the expected characteristics. Thetype of the additional resin is not particularly limited as long as theresin has insulating properties. Examples thereof include resins such asepoxy resins, benzoxazine compounds, phenol resins, thermoplasticresins, and silicone resins. Appropriately combined use with theseresins can impart metal adhesion to a prepreg and a resin sheet and canimpart stress-relaxing properties to a printed circuit board or thelike.

The resin composition of the present embodiment may contain a silanecompound having a group capable of being chemically bonded to an organicgroup, and a hydrolyzable group or a hydroxy group (hereinafter,referred to as an “additional silane compound”), except for theunsaturated bond-containing silane compound and the epoxysilanecompound, and/or a wetting dispersant in order to improve thedispersibility of the inorganic filler and the adhesion strength betweenthe resin and the inorganic filler or glass cloth. The additional silanecompound is not particularly limited and may be a silane coupling agentgenerally used in the surface treatment of inorganic substance. Specificexamples of the additional silane compound include: aminosilanecompounds having an amino group and a hydrolyzable group or a hydroxygroup, such as γ-aminopropyltriethoxysilane andN-β-(aminoethyl)-γ-aminopropyltrimethoxysilane; and mercaptosilanecompounds having a mercapto group and a hydrolyzable group or a hydroxygroup, such as γ-mercaptopropyltrimethoxysilane. These additional silanecompounds are used singly or in combinations of two or more thereof.

In the resin composition of the present embodiment, the content of theadditional silane compound is not particularly limited and is preferably0.1 to 15 parts by mass, more preferably 0.5 to 5 parts by mass, basedon 100 parts by mass in total of component(s) constituting a resin inthe resin composition. When the content of the additional silanecompound falls within such a range, a resin composition or the likehaving better desmear resistance and chemical resistance and havingbetter moldability even with an inorganic filler can be obtained, and aprinted circuit board or the like having better elastic modulus underheat can be obtained.

The wetting dispersant is not particularly limited as long as thewetting dispersant is used as a dispersion stabilizer for paint.Examples of commercially available products of the wetting dispersantinclude Disperbyk-110, 111, 118, 180, 161, 2009, BYK-W996, W9010, andW903 (all are product names) manufactured by BYK Japan K.K. Thesewetting dispersants are used singly or in combinations of two or morethereof

The resin composition of the present embodiment may be used incombination with a curing accelerator without impairing expectedcharacteristics. Examples of the curing accelerator include: imidazolecompounds; organic peroxides such as benzoyl peroxide, lauroyl peroxide,acetyl peroxide, p-chlorobenzoyl peroxide, anddi-tert-butyl-di-perphthalate; azo compounds such as azobisnitrile;tertiary amines such as N,N-dimethylbenzylamine, N,N-dimethylaniline,N,N-dimethyltoluidine, 2-N-ethylanilinoethanol, tri-n-butylamine,pyridine, quinoline, N-methylmorpholine, triethanolamine,triethylenediamine, tetramethylbutanediamine, and N-methylpiperidine;phenols such as phenol, xylenol, cresol, resorcin, and catechol; organicmetal salts such as lead naphthenate, lead stearate, zinc naphthenate,zinc octoate, tin oleate, dibutyl tin maleate, manganese naphthenate,cobalt naphthenate, and acetyl acetone iron; these organic metal saltsdissolved in hydroxy group-containing compounds such as phenol andbisphenol; inorganic metal salts such as tin chloride, zinc chloride,and aluminum chloride; and dioctyl tin oxide and other organic tincompounds such as alkyl tin and alkyl tin oxide. These curingaccelerators are used singly or in combinations of two or more thereof.

The resin composition of the present embodiment preferably furthercontains an imidazole compound among the curing accelerators describedabove. The imidazole compound is not particularly limited and ispreferably an imidazole compound represented by the following formula(11) in view of more effectively and reliably exhibiting the functioneffects of the present invention.

In this formula, Ar represents a phenyl group, a naphthalene group, abiphenyl group, or an anthracene group, or a monovalent group thereofmodified with a hydroxy group and is particularly preferably a phenylgroup. R₁₇ represents a hydrogen atom, an alkyl group or a monovalentgroup thereof modified with a hydroxy group, or an aryl group. Examplesof the aryl group include a substituted or unsubstituted phenyl group,naphthalene group, biphenyl group, and anthracene group. A phenyl groupis preferred. More preferably, both of the Ar group and the R₁₇ groupare phenyl groups.

Examples of the imidazole compound include 2-methylimidazole,2-ethyl-4-methylimidazole, 2-phenylimidazole,1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole,2-phenyl-4,5-dihydroxymethylimidazole,2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4,5-triphenylimidazole,and 2-phenyl-4-methylimidazole. Among them, 2,4,5-triphenylimidazole or2-phenyl-4-methylimidazole is more preferred, and2,4,5-triphenylimidazole is particularly preferred.

In the resin composition of the present embodiment, the content of theimidazole compound is not particularly limited and is preferably 0.01 to10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100parts by mass in total of component(s) constituting a resin in the resincomposition. When the content of the imidazole compound falls withinsuch a range, a resin composition, a prepreg, and a resin sheetexcellent in curability and moldability can be obtained.

The resin composition of the present embodiment may further contain asurface conditioner for the purpose of, for example, improving thedispersibility of solid material such as the inorganic filler. Thesurface conditioner is not particularly limited as long as the surfaceconditioner is a surfactant conventionally contained in resincompositions. Examples thereof include polydimethylsiloxane derivativesand acrylic derivatives. Examples of commercially available productsthereof include BYK-310, 330, and 346 manufactured by BYK Japan K.K.These surface conditioners are used singly or in combinations of two ormore thereof.

The resin composition of the present embodiment may also contain asolvent, if necessary. For example, use of an organic solvent reducesviscosity during the preparation of the resin composition and thusimproves handleability while enhancing the impregnation of glass clothwith the resin composition. The type of the solvent is not particularlylimited as long as the solvent is capable of dissolving a portion or thewhole of the resins in the resin composition. Specific examples thereofinclude, but are not particularly limited to: ketones such as acetone,methyl ethyl ketone, and methylcellosolve; aromatic hydrocarbons such astoluene and xylene; amides such as dimethylformamide; and propyleneglycol monomethyl ether and its acetate. These solvents are used singlyor in combinations of two or more thereof.

The resin composition of the present embodiment can be prepared inaccordance with an ordinary method. For example, a preferred methodinvolves obtaining a resin composition homogeneously containing thecomponents mentioned above. Specifically, for example, the componentsmentioned above can be sequentially added to the solvent andsufficiently stirred to readily prepare the resin composition of thepresent embodiment. The unsaturated bond-containing silane compound andthe epoxysilane compound may be contained in the resin composition, aswith other components. Alternatively or additionally to this, theinorganic filler may be surface-treated with the unsaturatedbond-containing silane compound and/or the epoxysilane compound, and theinorganic filler bonded at its surface to the silane compound(s) canthen be mixed with other components to prepare the resin composition.The method for surface-treating the inorganic filler with theunsaturated bond-containing silane compound and/or the epoxysilanecompound is not particularly limited. Examples thereof include directtreatment methods such as a dry treatment method and a treatment methodusing slurry (wet method). A wet method is preferred in view of uniformtreatment. Alternatively, a commercially available surface-treatedinorganic filler (filler) may be used.

An organic solvent may be used, if necessary, in the preparation of theresin composition of the present embodiment. The type of the organicsolvent is not particularly limited as long as the solvent is capable ofdissolving the resins in the resin composition. Specific examplesthereof are as listed above. Treatment (stirring, mixing, or kneadingtreatment, etc.) known in the art for uniformly dissolving or dispersingeach component can be carried out in the preparation of the resincomposition. In the case of using, for example, the inorganic filler,the inorganic filler can be uniformly dispersed by stirring anddispersion treatment using a stirring vessel equipped with a stirrerhaving an appropriate stirring ability. This enhances the dispersibilityof the inorganic filler (D) in the resin composition. The stirring,mixing, or kneading treatment can be appropriately performed by using anapparatus known in the art such as an apparatus aimed at mixing such asa ball mill or a bead mill, or a revolution- or rotation-type mixingapparatus.

The prepreg of the present embodiment is a prepreg including a basematerial and the resin composition, the base material being impregnatedor coated with the resin composition. The method for producing theprepreg can be carried out in accordance with an ordinary method withoutparticular limitations. For example, the base material can beimpregnated or coated with the resin components according to the presentembodiment, followed by semi-curing (conversion to B-staging) by heatingor the like for 1 to 30 minutes in a drier of 100 to 200° C. to preparethe prepreg of the present embodiment.

The content of the resin composition (containing the inorganic filler)is not particularly limited and is preferably 30 to 90% by mass, morepreferably 35 to 85% by mass, further preferably 40 to 80% by mass,based on the total mass of the prepreg. When the content of the resincomposition falls within the range described above, moldability tends tobe further improved.

The base material is not particularly limited and can be appropriatelyselected for use from various printed circuit board materials known inthe art according to the intended use or performance. Specific examplesthereof include, but are not particularly limited to: glass fibers suchas E glass, D glass, S glass, Q glass, spherical glass, NE glass, Lglass, and T glass; non-glass inorganic fibers such as quartz; whollyaromatic polyamides such as poly-p-phenyleneterephthalamide (Kevlar®,manufactured by Du Pont K.K.) andco-poly-p-phenylene/3,4′-oxydiphenylene/terephthalamide (Technora®,manufactured by Teijin Techno Products, Ltd.); polyesters such as2,6-hydroxynaphthoic acid/p-hydroxybenzoic acid (Vectran®, manufacturedby Kuraray Co., Ltd.) and Zexion® (manufactured by KB Seiren, Ltd.); andorganic fibers such as poly-p-phenylene benzoxazole (Zylon®,manufactured by Toyobo Co., Ltd.) and polyimide. Among them, E glass, Tglass, S glass, Q glass, or an organic fiber is preferred in view of alow coefficient of thermal expansion. These base materials may be usedsingly or in combinations of two or more thereof.

Examples of the form of the base material include, but are notparticularly limited to, woven fabrics, nonwoven fabrics, lobings,chopped strand mats, and surfacing mats. The textures of the wovenfabrics are not particularly limited, and, for example, plain weave, matweave, and twill weave are known. The base material can be appropriatelyselected for use from these materials known in the art according to theintended use or performance. Such a base material subjected to openingtreatment or a glass woven fabric surface-treated with a silane compound(e.g., a silane coupling agent) or the like is preferably used. The basematerial is not particularly limited by its thickness and mass. Usually,the thickness of the base material of approximately 0.01 to 0.3 mm ispreferably used. In particular, the base material is preferably a glasswoven fabric having a thickness of 200 μm or smaller and a mass of 250g/m² or smaller, more preferably a woven fabric (cloth) made of one ormore fibers selected from the group consisting of E glass, S glass, Tglass, and Q glass fibers, and an organic fiber in view of strength andwater absorbability.

The resin sheet of the present embodiment includes a support (sheet basematerial) and the resin composition, the sheet base material beingcoated with the resin composition. The resin composition is laminated onone side or both sides of the sheet base material. The resin sheet isused as an approach for thinning and can be produced, for example, bydirectly coating a support such as a metal foil or a film with athermosetting resin (containing an inorganic filler) for use inprepregs, etc., followed by drying.

The sheet base material is not particularly limited, and any of variousprinted circuit board materials known in the art can be used. Examplesthereof include polyimide films, polyamide films, polyester films,polyethylene terephthalate (PET) films, polybutylene terephthalate (PBT)films, polypropylene (PP) films, polyethylene (PE) films, aluminumfoils, copper foils, and gold foils. Among them, an electrolytic copperfoil or a PET film is preferred.

Examples of the coating method include a method of applying a solutioncontaining the resin composition of the present embodiment dissolved ina solvent onto the sheet base material using a bar coater, a die coater,a doctor blade, a Baker applicator, or the like.

The resin sheet is preferably a product obtained by coating the support(sheet base material) with the resin composition, followed bysemi-curing (conversion to B-staging) the resin composition. Specificexamples thereof include a method which involves coating the sheet basematerial such as a copper foil with the resin composition, followed bysemi-curing the resin composition by a method such as heating for 1 to60 minutes in a drier of 100 to 200° C. to produce the resin sheet. Theamount of the resin composition applied to the support is preferably inthe range of 1 to 300 m in terms of the resin thickness of the resinsheet. The resin sheet of the present embodiment can be used as abuildup material for printed circuit boards.

The laminate of the present embodiment has one or more layers of atleast one material selected from the group consisting of theaforementioned prepreg and resin sheet and includes a cured product ofthe resin composition contained in at least one material selected fromthe group consisting of the aforementioned prepreg and resin sheet. Thislaminate can be obtained by curing one or more layers of at least onematerial selected from the group consisting of the aforementionedprepreg and resin sheet. The metal foil-clad laminate of the presentembodiment is a metal foil-clad laminate having at least one materialselected from the group consisting of the aforementioned prepreg andresin sheet, and a metal foil disposed on one side or both sides of atleast one material selected from the group consisting of theaforementioned prepreg and resin sheet, the metal foil-clad laminateincluding a cured product of the resin composition contained in at leastone material selected from the group consisting of the aforementionedprepreg and resin sheet. This metal foil-clad laminate can be obtainedby providing one or more layers of at least one material selected fromthe group consisting of the aforementioned prepreg and resin sheet, anddisposing the metal foil on one side or both sides thereof, followed bylaminate molding. More specifically, the metal foil-clad laminate can beproduced by laminating one or more layers of the aforementioned prepregand/or resin sheet, disposing the metal (e.g., copper or aluminum) foilon one side or both sides thereof if desired, and carrying out laminatemolding of this structure according to the need. In this context, themetal foil used is not particularly limited as long as the metal foilcan be used as a printed circuit board material. A copper foil known inthe art such as a rolled copper foil or an electrolytic copper foil ispreferred. The thickness of the metal foil is not particularly limitedand is preferably 1 to 70 μm, more preferably 1.5 to 35 μm. The metalfoil-clad laminate is not particularly limited by its molding method andmolding conditions and can be molded by use of a general approach andconditions for laminates for printed circuit boards and multilayerboards. For example, a multiplaten press, a multiplaten vacuum press, acontinuous molding machine, or an autoclave molding machine can be usedin the molding of the metal foil-clad laminate. The metal foil-cladlaminate is generally molded at a temperature of 100 to 300° C. and apressure of 2 to 100 kgf/cm² in terms of surface pressure for a heatingtime in the range of 0.05 to 5 hours. If necessary, post curing may befurther carried out at a temperature of 150 to 300° C. Alternatively,the laminate molding of the prepreg mentioned above may be carried outin combination with a separately prepared wiring board for an innerlayer to obtain a multilayer board.

The printed circuit board of the present embodiment is a printed circuitboard including an insulating layer and a conductor layer formed on thesurface of the insulating layer, wherein the insulating layer containsthe resin composition mentioned above. The conductor layer that servesas a circuit can be formed from the metal foil in the metal foil-cladlaminate mentioned above or can be formed by electroless plating on theinsulating layer. This printed circuit board attains a high glasstransition temperature of an insulating layer, is excellent in heatresistance after moisture absorption and insulation reliability and canbe particularly effectively used as a printed circuit board forsemiconductor packages required to have such performance.

Specifically, the printed circuit board of the present embodiment can beproduced by, for example, the following method: first, the metalfoil-clad laminate (copper-clad laminate, etc.) mentioned above isprepared. The surface of the metal foil-clad laminate is subjected toetching treatment for the formation of an inner layer circuit to preparean inner layer substrate. The inner layer circuit surface of this innerlayer substrate is subjected, if necessary, to surface treatment forenhancing adhesion strength. Subsequently, a required number of theprepreg mentioned above is laminated on the resulting inner layercircuit surface. A metal foil for an outer layer circuit is laterallylaminated thereon, followed by integral molding under heat and pressure.In this way, a multilayer laminate is produced in which the insulatinglayer composed of the base material and a cured product of thermosettingresin composition is formed between the inner layer circuit and themetal foil for an outer layer circuit. Subsequently, this multilayerlaminate is subjected to hole-making processing for making through-holesor via holes and then subjected to desmear treatment for removing smear,which is a residue of resins derived from the resin components containedin the cured product layer. Then, the inside walls of these holes arecoated with a metal plating film for conducting the inner layer circuitand the metal foil for an outer layer circuit. The metal foil for anouter layer circuit is further subjected to etching treatment for theformation of the outer layer circuit to produce the printed circuitboard.

For example, the prepreg mentioned above (base material impregnated withthe resin composition mentioned above) or the resin composition layer ofthe metal foil-clad laminate (layer composed of the resin compositionmentioned above) constitutes the insulating layer including the resincomposition mentioned above.

In the present embodiment, the ratio of the flexural modulus at 250° C.to the flexural modulus at 25° C. (hereinafter, referred to as the “rateof elastic modulus maintenance”) of the insulating layer is preferably80 to 100% because warpage caused by the heating of the printed circuitboard can be suppressed. Examples of an approach for adjusting the rateof elastic modulus maintenance to 80 to 100% include, but are notparticularly limited to, appropriately adjusting the type and content ofeach component of the resin composition for use in the insulating layerwithin the ranges described above. The rate of elastic modulusmaintenance is specifically determined by the following method: theflexural modulus (bending strength) is measured at each of 25° C. and250° C. using an autograph according to a method specified by JIS C6481. From the measured flexural modulus at 25° C. (a) and flexuralmodulus under heat at 250° C. (b), the rate of elastic modulusmaintenance is calculated according to the following formula:

Rate of elastic modulus maintenance=(b)/(a)×100

Alternatively or additionally to this approach, the rate of elasticmodulus maintenance may be adjusted to 80 to 100% by use of an existingmethod as long as it does not hinder the object of the presentinvention. Examples thereof include restricting molecular motion by theintroduction of nanofiller, hybridizing nanosilica by a sol-gel methodto a crosslinking point in a resin for use in the insulating layer,achieving high Tg of a resin itself for use in the insulating layer, andrendering the resin Tg-less in a region of 400° C. or lower.

When the metal foil-clad laminate is not used, the printed circuit boardmay be prepared by forming the conductor layer that serves as a circuiton the prepreg or the resin sheet. In this case, an electroless platingapproach may be used for forming the conductor layer.

The printed circuit board of the present embodiment can be particularlyeffectively used as a printed circuit board for semiconductor packages,because the insulating layer mentioned above maintains the excellentelastic modulus even at a reflow temperature during semiconductorpackaging and thereby effectively suppresses the warpage ofsemiconductor plastic packages. Also, the metal foil-clad laminate isexcellent in heat resistance after moisture absorption and insulationreliability and can be particularly effectively used as a printedcircuit board for semiconductor packages required to have suchperformance.

EXAMPLES

Hereinafter, the present invention will be described in more detail withreference to Examples. However, the present invention is not intended tobe limited by these Examples.

(Synthesis Example 1) Synthesis of α-Naphthol Aralkyl-Based CyanateEster Resin

A reactor equipped with a thermometer, a stirrer, a dropping funnel, anda reflux condenser was cooled to 0 to 5° C. in advance using brine andcharged with 7.47 g (0.122 mol) of cyanogen chloride, 9.75 g (0.0935mol) of 35% hydrochloric acid, 76 mL of water, and 44 mL of methylenechloride. While the temperature and pH of this reactor were kept at −5to +5° C. and 1 or lower, respectively, a solution containing 20 g(0.0935 mol) of an α-naphthol aralkyl-based phenol resin of the formula(9) wherein all of the R₈ were hydrogen atoms (SN485, OH groupequivalent: 214 g/eq., softening point: 86° C., manufactured by NipponSteel & Sumikin Chemical Co., Ltd.), and 14.16 g (0.14 mol) oftriethylamine dissolved in 92 mL of methylene chloride was addeddropwise over 1 hour through the dropping funnel with stirring. Afterthe completion of the dropwise addition, 4.72 g (0.047 mol) oftriethylamine was further added dropwise thereto over 15 minutes. Afterthe completion of the dropwise addition, the mixture was stirred at thesame temperature as above for 15 minutes. Then, the reaction solutionwas separated into organic and aqueous layers, and the organic layer wasseparated. The obtained organic layer was washed with 100 mL of watertwice. Then, methylene chloride was distilled off under reduced pressurewith an evaporator, and the residue was finally concentrated to drynessat 80° C. for 1 hour to obtain 23.5 g of a cyanate ester product of theα-naphthol aralkyl-based phenol resin (α-naphthol aralkyl-based cyanateester resin, functional group equivalent: 261 g/eq.).

Example 1

10 parts by mass of the α-naphthol aralkyl-based cyanate ester resinobtained by Synthesis Example 1, 45 parts by mass of a novolac-basedmaleimide compound (BMI-2300, manufactured by Daiwa Fine Chemicals Co.,Ltd., functional group equivalent: 186 g/eq.), and 45 parts by mass ofbisallylnadimide (BANI-M, manufactured by Maruzen Petrochemical Co.,Ltd., functional group equivalent: 286 g/eq.) were mixed with 200 partsby mass of spherical silica (SC-5050MOB, particle size: 1.6 μm,manufactured by Admatechs Co., Ltd.), 2.5 parts by mass of anepoxysilane compound 3-glycidoxypropyltrimethoxysilane (KBM-403,manufactured by Shin-Etsu Chemical Co., Ltd.), 2.5 parts by mass of astyryl silane compound p-styryltrimethoxysilane (KBM-1403, manufacturedby Shin-Etsu Chemical Co., Ltd.), and 1 part by mass of a wettingdispersant (DISPERBYK-161, manufactured by BYK Japan K.K.), and themixture was diluted with methyl ethyl ketone to obtain varnish. An Eglass woven fabric was impregnated and coated with this varnish, anddried by heating at 160° C. for 3 minutes to obtain a prepreg having aresin composition content of 49% by mass. In this respect, the ratio[β/α] was 1.54. In this context, the ratio [β/α] is represented by thefollowing formula (the same holds true for the description below):

[β/α]=(Parts by mass of the maleimide compound/Functional groupequivalent of the maleimide compound)/(Parts by mass of thealkenyl-substituted nadimide/Functional group equivalent of thealkenyl-substituted nadimide)

Example 2

Varnish was obtained in the same way as in Example 1, and a prepreg wasobtained in the same way as in Example 1, except that 2.5 parts by massof the epoxysilane compound 3-glycidoxypropyltrimethoxysilane (KBM-403,manufactured by Shin-Etsu Chemical Co., Ltd.) and 2.5 parts by mass ofan acrylic silane compound 3-acryloxypropyltrimethoxysilane (KBM-5103,manufactured by Shin-Etsu Chemical Co., Ltd.) were used instead of 2.5parts by mass of the epoxysilane compound3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-EtsuChemical Co., Ltd.) and 2.5 parts by mass of the styryl silane compoundp-styryltrimethoxysilane (KBM-1403, manufactured by Shin-Etsu ChemicalCo., Ltd.).

Example 3

Varnish was obtained in the same way as in Example 1, and a prepreg wasobtained in the same way as in Example 1, except that 2.5 parts by massof the epoxysilane compound 3-glycidoxypropyltrimethoxysilane (KBM-403,manufactured by Shin-Etsu Chemical Co., Ltd.) and 2.5 parts by mass ofan olefin silane compound vinyltrimethoxysilane (KBM-1003, manufacturedby Shin-Etsu Chemical Co., Ltd.) were used instead of 2.5 parts by massof the epoxysilane compound 3-glycidoxypropyltrimethoxysilane (KBM-403,manufactured by Shin-Etsu Chemical Co., Ltd.) and 2.5 parts by mass ofthe styryl silane compound p-styryltrimethoxysilane (KBM-1403,manufactured by Shin-Etsu Chemical Co., Ltd.).

Example 4

Varnish was obtained in the same way as in Example 1, and a prepreg wasobtained in the same way as in Example 1, except that 2.5 parts by massof an epoxysilane compound 3-glycidoxypropyltrimethoxysilane (KBM-403,manufactured by Shin-Etsu Chemical Co., Ltd.) and 2.5 parts by mass ofan olefin silane compound octenyltrimethoxysilane (KBM-1083,manufactured by Shin-Etsu Chemical Co., Ltd.) were used instead of 2.5parts by mass of the epoxysilane compound3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-EtsuChemical Co., Ltd.) and 2.5 parts by mass of the styryl silane compoundp-styryltrimethoxysilane (KBM-1403, manufactured by Shin-Etsu ChemicalCo., Ltd.).

Comparative Example 1

Varnish was obtained in the same way as in Example 1, and a prepreg wasobtained in the same way as in Example 1, except that 5 parts by mass ofan acrylic silane compound 3-acryloxypropyltrimethoxysilane (KBM-5103,manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of 2.5parts by mass of the epoxysilane compound3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-EtsuChemical Co., Ltd.) and 2.5 parts by mass of the styryl silane compoundp-styryltrimethoxysilane (KBM-1403, manufactured by Shin-Etsu ChemicalCo., Ltd.).

Comparative Example 2

Varnish was obtained in the same way as in Example 1, and a prepreg wasobtained in the same way as in Example 1, except that 5 parts by mass ofthe styryl silane compound p-styryltrimethoxysilane (KBM-1403,manufactured by Shin-Etsu Chemical Co., Ltd.) were used instead of 2.5parts by mass of the epoxysilane compound3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-EtsuChemical Co., Ltd.) and 2.5 parts by mass of the styryl silane compoundp-styryltrimethoxysilane (KBM-1403, manufactured by Shin-Etsu ChemicalCo., Ltd.).

Comparative Example 3

Varnish was obtained in the same way as in Example 1, and a prepreg wasobtained in the same way as in Example 1, except that 5 parts by mass ofan olefin silane compound octenyltrimethoxysilane (KBM-1083,manufactured by Shin-Etsu Chemical Co., Ltd.) were used instead of 2.5parts by mass of the epoxysilane compound3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-EtsuChemical Co., Ltd.) and 2.5 parts by mass of the styryl silane compoundp-styryltrimethoxysilane (KBM-1403, manufactured by Shin-Etsu ChemicalCo., Ltd.).

Comparative Example 4

Varnish was obtained in the same way as in Example 1, and a prepreg wasobtained in the same way as in Example 1, except that 5 parts by mass ofan acrylic silane compound methacryloxyoctyltrimethoxysilane (KBM-5803,manufactured by Shin-Etsu Chemical Co., Ltd.) were used instead of 2.5parts by mass of the epoxysilane compound3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-EtsuChemical Co., Ltd.) and 2.5 parts by mass of the styryl silane compoundp-styryltrimethoxysilane (KBM-1403, manufactured by Shin-Etsu ChemicalCo., Ltd.).

Comparative Example 5

Varnish was obtained in the same way as in Example 1, and a prepreg wasobtained in the same way as in Example 1, except that 5 parts by mass ofthe olefin silane compound vinyltrimethoxysilane (KBM-1003, manufacturedby Shin-Etsu Chemical Co., Ltd.) were used instead of 2.5 parts by massof the epoxysilane compound 3-glycidoxypropyltrimethoxysilane (KBM-403,manufactured by Shin-Etsu Chemical Co., Ltd.) and 2.5 parts by mass ofthe styryl silane compound p-styryltrimethoxysilane (KBM-1403,manufactured by Shin-Etsu Chemical Co., Ltd.).

[Preparation of Metal Foil-Clad Laminate]

Electrolytic copper foils having a thickness of 12 μm (3EC-III,manufactured by Mitsui Mining & Smelting Co., Ltd.) were disposed on theupper and lower sides of 1 layer, 4 layers, or 8 layers of the prepregthus obtained, and laminate molding of the resultant was carried out ata pressure of 30 kgf/cm² and a temperature of 220° C. for 120 minutes toobtain a copper-clad laminate having an insulating layer thickness of0.1 mm, 0.2 mm, or 0.8 mm as a metal foil-clad laminate.

[Insulation Reliability]

The insulation reliability was evaluated by the interwinding insulationreliability test based on HAST (highly accelerated temperature andhumidity stress test). First, a printed circuit board (L/S=100/100 μm)was formed by the subtractive method from the copper-clad laminate (aninsulating layer thickness: 0.2 mm) thus obtained. Next, a power wasconnected to the wiring, and continuous humidity insulation resistancewas evaluated under conditions involving a temperature of 130° C., ahumidity of 85%, and an applied voltage of 5 VDC. A resistance valueequal to or lower than 1.0×10⁸ Ω was regarded as a breakdown. Theevaluation criteria are as described below.

◯: No breakdown occurred for 500 hours or longer

x: A breakdown occurred in less than 500 hours.

The results are shown in Table 1.

[Moldability]

The copper foils were removed from the copper-clad laminate (insulatinglayer thickness: 0.1 mm) by etching. Then, the surfaces were observed toevaluate the presence or absence of voids. A sample having favorableappearance without any formed void was evaluated as “⊚”; a sampleconfirmed to have voids formed only at the end portion was evaluated as“◯”; and a sample confirmed to have voids formed throughout the surfaceswas evaluated as “x”. The results are shown in Table 1.

[Heat Resistance after Moisture Absorption]

The copper foils were removed from both sides of the copper-cladlaminate (50 mm×50 mm×insulating layer thickness of 0.8 mm) except forhalf the surface on one side by etching to obtain a test specimen. Theobtained test specimen was treated with a pressure cooker tester(manufactured by Hirayama Manufacturing Corp., Model PC-3) at 121° C. at2 atm for 5 hours and then dipped in solder of 288° C. for 30 seconds.Three samples were each subjected to the test described above. Thepresence or absence of swelling after the dipping was visually observed,and the heat resistance after moisture absorption was evaluatedaccording to the following evaluation criteria.

◯w No abnormality was found.

xN Swelling occurred.

The results are shown in Table 1.

TABLE 1 Example Example Example Example Comparative ComparativeComparative Comparative Comparative 1 2 3 4 Example 1 Example 2 Example3 Example 4 Example 5 Insulation ◯ ◯ ◯ ◯ ◯ ◯ X X X reliabilityMoldability ⊚ ⊚ ◯ ◯ X X X X X Heat resistance ◯ ◯ ◯ ◯ ◯ ◯ X X X aftermoisture absorption

The present application is based on Japanese Patent Application No.2015-135206 filed on Jul. 6, 2015, the contents of which areincorporated herein by reference.

INDUSTRIAL APPLICABILITY

The present invention can provide a metal foil-clad laminate and aprinted circuit board excellent in heat resistance after moistureabsorption, and a resin composition, a prepreg, and a resin sheet thatserve as raw materials therefor and are excellent in moldability, and istherefore industrially applicable to fields such as printed circuitboards for use in semiconductor plastic packages.

1. A resin composition comprising a maleimide compound, a silanecompound having a carbon-carbon unsaturated bond and a hydrolyzablegroup or a hydroxy group, a silane compound having an epoxy skeleton anda hydrolyzable group or a hydroxy group, and an inorganic filler.
 2. Theresin composition according to claim 1, wherein the resin compositioncomprises, as the silane compound having a carbon-carbon unsaturatedbond and a hydrolyzable group or a hydroxy group, a silane compoundhaving a styrene skeleton and a hydrolyzable group or a hydroxy group,and/or a silane compound having a (meth)acryl skeleton and ahydrolyzable group or a hydroxy group.
 3. The resin compositionaccording to claim 2, wherein the resin composition comprises, as thesilane compound having a carbon-carbon unsaturated bond and ahydrolyzable group or a hydroxy group, a silane compound having astyrene skeleton and a hydrolyzable group or a hydroxy group.
 4. Theresin composition according to claim 2 or 3, wherein the resincomposition comprises, as the silane compound having a styrene skeletonand a hydrolyzable group or a hydroxy group, a compound represented bythe following formula (A):

wherein R₈ represents the hydrolyzable group or the hydroxy group; R₉represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms;when a plurality of R₈ or R₉ are present, the plurality of R₈ or R₉ arethe same as or different from each other; and k represents an integer of1 to
 3. 5. The resin composition according to claim 2, wherein the resincomposition comprises, as the silane compound having a (meth)acrylskeleton and a hydrolyzable group or a hydroxy group, a compoundrepresented by the following formula (C):

wherein R₁₃ represents the hydrolyzable group or the hydroxy group; R₁₄represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms;when a plurality of R₁₃ or R₁₄ are present, the plurality of R₁₃ or R₁₄are the same as or different from each other; R₁₅ represents a hydrogenatom or a methyl group; R₁₆ represents an alkylene group having 2 to 10carbon atoms; and j represents an integer of 1 to
 3. 6. The resincomposition according to claim 1, wherein the resin compositioncomprises, as the silane compound having an epoxy skeleton and ahydrolyzable group or a hydroxy group, a compound represented by thefollowing formula (D):

wherein R₁₀ represents the hydrolyzable group or the hydroxy group; R₁₁represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms;when a plurality of R₁₀ or R₁₁ are present, the plurality of R₁₀ or R₁₁are the same as or different from each other; R₁₂ represents an alkylenegroup having 1 to 10 carbon atoms; and m represents an integer of 1 to3.
 7. The resin composition according to claim 1, further comprising analkenyl-substituted nadimide.
 8. The resin composition according toclaim 7, wherein the resin composition comprises, as thealkenyl-substituted nadimide, a compound represented by the followingformula (1):

wherein each R₁ independently represents a hydrogen atom or an alkylgroup having 1 to 6 carbon atoms, and R₂ represents an alkylene grouphaving 1 to 6 carbon atoms, a phenylene group, a biphenylene group, anaphthylene group, or a group represented by the following formula (2)or (3):

wherein R₃ represents a methylene group, an isopropylidene group, or asubstituent represented by CO, O, S, or SO₂, and

wherein each R₄ independently represents an alkylene group having 1 to 4carbon atoms, or a cycloalkylene group having 5 to 8 carbon atoms. 9.The resin composition according to claim 7, wherein the resincomposition comprises, as the alkenyl-substituted nadimide, a compoundrepresented by the following formula (4) and/or (5):


10. The resin composition according to claim 1, wherein the resincomposition comprises, as the maleimide compound, at least one compoundselected from the group consisting of bis(4-maleimidophenyl)methane,2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane,bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, polytetramethyleneoxide-bis(4-maleimidobenzoate), and a maleimide compound represented bythe following formula (6):

wherein each R₅ independently represents a hydrogen atom or a methylgroup, and n₁ represents an integer of 1 or larger.
 11. The resincomposition according to claim 1, further comprising a cyanate estercompound.
 12. The resin composition according to claim 11, wherein theresin composition comprises, as the cyanate ester compound, a compoundrepresented by the following formula (7) and/or (8):

wherein each R₆ independently represents a hydrogen atom or a methylgroup, and n₂ represents an integer of 1 or larger, and

wherein each R₇ independently represents a hydrogen atom or a methylgroup, and n₃ represents an integer of 1 or larger.
 13. The resincomposition according to claim 1, wherein the inorganic filler comprisesat least one selected from the group consisting of silica, alumina, andaluminum nitride.
 14. The resin composition according to claim 1,wherein the content of the inorganic filler in the resin composition is100 to 1100 parts by mass based on 100 parts by mass in total ofcomponent(s) constituting a resin in the resin composition.
 15. Theresin composition according to claim 1, wherein the inorganic filler issurface-treated in advance with the silane compound having acarbon-carbon unsaturated bond and a hydrolyzable group or a hydroxygroup, and the silane compound having an epoxy skeleton and ahydrolyzable group or a hydroxy group.
 16. (canceled)
 17. (canceled) 18.(canceled)
 19. (canceled)
 20. A metal foil-clad laminate having at leastone material selected from the group consisting of a prepreg comprisinga base material and a resin composition according to claim 1, the basematerial being impregnated or coated with the resin composition and aresin sheet comprising a support and the resin composition, the supportbeing coated with the resin composition, and a metal foil disposed onone side or both sides of at least one material selected from the groupconsisting of the prepreg and the resin sheet, the metal foil-cladlaminate comprising a cured product of the resin composition containedin at least one material selected from the group consisting of theprepreg and the resin sheet.
 21. A printed circuit board comprising aninsulating layer and a conductor layer formed on a surface of theinsulating layer, wherein the insulating layer comprises a resincomposition according to claim 1.